Philipp Roesler, who’s also Germany’s economy minister, appealed to his pro-market Free Democratic Party on Sunday to show unity ahead of a state election in his home region of Lower Saxony on Jan. 20, an important political test ahead of national elections in September.

Polls suggest the center-left opposition has a good chance of winning Lower Saxony from Merkel’s center-right alliance — largely because the FDP is very weak. The party’s poll ratings haven’t improved since Roesler became leader in 2011 and prominent members have openly aired frustration, fueling speculation he could be replaced.